You might try reviewing your 2018 return carefully with respect to the information for the "dropped" member; it could be that the member was somehow shown as having disposed of his/her interest or otherwise left the LLC.
Beyond that, you might want to contact Support (link below) during regular business hours for troubleshooting this issue.
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632
